This invention relates to compositions and methods for modulating expression of p38 mitogen activated protein kinase genes, a family of naturally present cellular genes involved in signal transduction, and inflammatory and apoptotic responses. This invention is also directed to methods for inhibiting inflammation or apoptosis; these methods can be used diagnostically or therapeutically. Furthermore, this invention is directed to treatment of diseases or conditions associated with expression of p38 mitogen activated protein kinase genes.
Cellular responses to external factors, such as growth factors, cytokines, and stress conditions, result in altered gene expression. These signals are transmitted from the cell surface to the nucleus by signal transduction pathways. Beginning with an external factor binding to an appropriate receptor, a cascade of signal transduction events is initiated. These responses are mediated through activation of various enzymes and the subsequent activation of specific transcription factors. These activated transcription factors then modulate the expression of specific genes.
The phosphorylation of enzymes plays a key role in the transduction of extracellular signals into the cell. Mitogen activated protein kinases (MAPKs), enzymes which effect such phosphorylations are targets for the action of growth factors, hormones, and other agents involved in cellular metabolism, proliferation and differentiation (Cobb et al., J. Biol. Chem., 1995, 270, 14843). Mitogen activated protein kinases were initially discovered due to their ability to be tyrosine phosphorylated in response to exposure to bacterial lipopolysaccharides or hyperosmotic conditons (Han et al, Science, 1994, 265, 808). These conditions activate inflammatory and apoptotic responses mediated by MAPK. In general, MAP kinases are involved in a variety of signal transduction pathways (sometimes overlapping and sometimes parallel) that function to convey extracellular stimuli to protooncogene products to modulate cellular proliferation and/or differentiation (Seger et al., FASEB J., 1995, 9, 726; Cano et al., Trends Biochem. Sci., 1995, 20, 117).
One of the MAPK signal transduction pathways involves the MAP kinases p38xcex1 and p38xcex2_(also known as CSaids Binding Proteins, CSBP). These MAP kinases are responsible for the phosphorylation of ATF-2, MEFC2 and a variety of other cellular effectors that may serve as substrates for p38 MAPK proteins (Kummer et al, J. Biol. Chem., 1997, 272, 20490). Phosphorylation of p38 MAPKs potentiates the ability of these factors to activate transcription (Raingeaud et al, Mol. Cell Bio., 1996, 16, 1247; Han et al, Nature, 1997, 386, 296). Among the genes activated by the p38 MAPK signaling pathway is IL-6 (De Cesaris, P., et al., J. Biol. Chem., 1998, 273, 7566-7571).
Besides p38xcex1 and p38xcex2, other p38 MAPK family members have been described, including p38xcex3 (Li et al, Biochem. Biophys. Res. Commun., 1996, 228, 334), and p38xcex4 (Jiang et al, J. Biol. Chem., 1997, 272, 30122). The term xe2x80x9cp38xe2x80x9d as used herein shall mean a member of the p38 MAPK family, including but not limited to p38xcex1, p38xcex2, p38xcex3 and p38xcex4, their isoforms (Kumar et al, Biochem. Biophys. Res. Commun., 1997, 235, 533) and other members of the p38 MAPK family of proteins whether they function as p38 MAP kinases per se or not.
Modulation of the expression of one or more p38 MAPKs is desirable in order to interfere with inflammatory or apoptotic responses associated with disease states and to modulate the transcription of genes stimulated by ATF-2, MEFC2 and other p38 MAPK phosphorylation substrates.
Inhibitors of p38 MAPKs have been shown to have efficacy in animal models of arthritis (Badger, A. M., et al., J. Pharmacol. Exp. Ther., 1996, 279, 1453-1461) and angiogenesis (Jackson, J. R., et al., J. Pharmacol. Exp. Ther., 1998, 284, 687-692). MacKay, K. and Mochy-Rosen, D. (J. Biol. Chem., 1999, 274, 6272-6279) demonstrate that an inhibitor of p38 MAPKs prevents apoptosis during ischemia in cardiac myocytes, suggesting that p38 MAPK inhibitors can be used for treating ischemic heart disease. p38 MAPK also is required for T-cell HIV-1 replication (Cohen et al, Mol. Med., 1997, 3, 339) and may be a useful target for AIDS therapy. Other diseases believed to be amenable to treatment by inhibitors of p38 MAPKs are disclosed in U.S. Pat. No. 5,559,137, herein incorporated by reference.
Therapeutic agents designed to target p38 MAPKs include small molecule inhibitors and antisense oligonucleotides. Small molecule inhibitors based on pyridinyl imidazole are described in U.S. Pat. Nos. 5,670,527; 5,658,903; 5,656,644; 5,559,137; 5,593,992; and 5,593,991. WO 98/27098 and WO 99/00357 describe additional small molecule inhibitors, one of which has entered clinical trials. Other small molecule inhibitors are also known.
Antisense therapy represents a potentially more specific therapy for targeting p38 MAPKs and, in particular, specific p38 MAPK isoforms. Nagata, Y., et al. (Blood, 1998, 6, 1859-1869) disclose an antisense phosphothioester oligonucleotide targeted to the translational start site of mouse p38b (p38xcex2). Aoshiba, K., et al. (J. Immunol., 1999, 162, 1692-1700) and Cohen, P. S., et al. (Mol. Med., 1997, 3, 339-346) disclose a phosphorothioate antisense oligonucleotide targeted to the coding regions of human p38xcex1, human p38xcex2 and rat p38.
There remains a long-felt need for improved compositions and methods for modulating the expression of p38 MAP kinases.
The present invention provides antisense compounds which are targeted to nucleic acids encoding a p38 MAPK and are capable of modulating p38 MAPK expression. The present invention also provides oligonucleotides targeted to nucleic acids encoding a p38 MAPK. The present invention also comprises methods of modulating the expression of a p38 MAPK, in cells and tissues, using the oligonucleotides of the invention. Methods of inhibiting p38 MAPK expression are provided; these methods are believed to be useful both therapeutically and diagnostically. These methods are also useful as tools, for example, for detecting and determining the role of p38 MAPKs in various cell functions and physiological processes and conditions and for diagnosing conditions associated with expression of p38 MAPKs.
The present invention also comprises methods for diagnosing and treating inflammatory diseases, particularly rheumatoid arthritis. These methods are believed to be useful, for example, in diagnosing p38 MAPK-associated disease progression. These methods employ the oligonucleotides of the invention. These methods are believed to be useful both therapeutically, including prophylactically, and as clinical research and diagnostic tools.
p38 MAPKs play an important role in signal transduction in response to cytokines, growth factors and other cellular stimuli. Specific responses elicited by p38 include inflammatory and apoptotic responses. Modulation of p38 may be useful in the treatment of inflammatory diseases, such as rheumatoid arthritis.
The present invention employs antisense compounds, particularly oligonucleotides, for use in modulating the function of nucleic acid molecules encoding a p38 MAPK, ultimately modulating the amount of a p38 MAPK produced. This is accomplished by providing oligonucleotides which specifically hybridize with nucleic acids, preferably mRNA, encoding a p38 MAPK.
The antisense compounds may be used to modulate the function of a particular p38 MAPK isoform, e.g. for research purposes to determine the role of a particular isoform in a normal or disease process, or to treat a disease or condition that may be associated with a particular isoform. It may also be desirable to target multiple p38 MAPK isoforms. In each case, antisense compounds can be designed by taking advantage of sequence homology between the various isoforms. If an antisense compound to a particular isoform is desired, then the antisense compound is designed to a unique region in the desired isoform""s gene sequence. With such a compound, it is desirable that this compound does not inhibit the expression of other isoforms. Less desirable, but acceptable, are compounds that do not xe2x80x9csubstantiallyxe2x80x9d inhibit other isoforms. By xe2x80x9csubstantiallyxe2x80x9d, it is intended that these compounds do not inhibit the expression of other isoforms greater than 25%; more preferred are compounds that do not inhibit other isoforms greater than 10%. If an antisense compound is desired to target multiple p38 isoforms, then regions of significant homology between the isoforms can be used.
This relationship between an antisense compound such as an oligonucleotide and its complementary nucleic acid target, to which it hybridizes, is commonly referred to as xe2x80x9cantisensexe2x80x9d. xe2x80x9cTargetingxe2x80x9d an oligonucleotide to a chosen nucleic acid target, in the context of this invention, is a multistep process. The process usually begins with identifying a nucleic acid sequence whose function is to be modulated. This may be, as examples, a cellular gene (or mRNA made from the gene) whose expression is associated with a particular disease state, or a foreign nucleic acid from an infectious agent. In the present invention, the target is a nucleic acid encoding a p38 MAPK; in other words, a p38 MAPK gene or RNA expressed from a p38 MAPK gene. p38 MAPK mRNA is presently the preferred target. The targeting process also includes determination of a site or sites within the nucleic acid sequence for the antisense interaction to occur such that modulation of gene expression will result.
In accordance with this invention, persons of ordinary skill in the art will understand that messenger RNA includes not only the information to encode a protein using the three letter genetic code, but also associated ribonucleotides which form a region known to such persons as the 5xe2x80x2-untranslated region, the 3xe2x80x2-untranslated region, the 5xe2x80x2 cap region and intron/exon junction ribonucleotides. Thus, oligonucleotides may be formulated in accordance with this invention which are targeted wholly or in part to these associated ribonucleotides as well as to the informational ribonucleotides. The oligonucleotide may therefore be specifically hybridizable with a transcription initiation site region, a translation initiation codon region, a 5xe2x80x2 cap region, an intron/exon junction, coding sequences, a translation termination codon region or sequences in the 5xe2x80x2- or 3xe2x80x2-untranslated region. Since, as is known in the art, the translation initiation codon is typically 5xe2x80x2-AUG (in transcribed mRNA molecules; 5xe2x80x2-ATG in the corresponding DNA molecule), the translation initiation codon is also referred to as the xe2x80x9cAUG codon,xe2x80x9d the xe2x80x9cstart codonxe2x80x9d or the xe2x80x9cAUG start codon.xe2x80x9d A minority of genes have a translation initiation codon having the RNA sequence 5xe2x80x2-GUG, 5xe2x80x2-UUG or 5xe2x80x2-CUG, and 5xe2x80x2-AUA, 5xe2x80x2-ACG and 5xe2x80x2-CUG have been shown to function in vivo. Thus, the terms xe2x80x9ctranslation initiation codonxe2x80x9d and xe2x80x9cstart codonxe2x80x9d can encompass many codon sequences, even though the initiator amino acid in each instance is typically methionine (in eukaryotes) or formylmethionine (prokaryotes). It is also known in the art that eukaryotic and prokaryotic genes may have two or more alternative start codons, any one of which may be preferentially utilized for translation initiation in a particular cell type or tissue, or under a particular set of conditions. In the context of the invention, xe2x80x9cstart codonxe2x80x9d and xe2x80x9ctranslation initiation codonxe2x80x9d refer to the codon or codons that are used in vivo to initiate translation of an mRNA molecule transcribed from a gene encoding p38, regardless of the sequence(s) of such codons. It is also known in the art that a translation termination codon (or xe2x80x9cstop codonxe2x80x9d) of a gene may have one of three sequences, i.e., 5xe2x80x2-UAA, 5xe2x80x2-UAG and 5xe2x80x2-UGA (the corresponding DNA sequences are 5xe2x80x2-TAA, 5xe2x80x2-TAG and 5xe2x80x2-TGA, respectively). The terms xe2x80x9cstart codon regionxe2x80x9d and xe2x80x9ctranslation initiation codon regionxe2x80x9d refer to a portion of such an mRNA or gene that encompasses from about 25 to about 50 contiguous nucleotides in either direction (i.e., 5xe2x80x2 or 3xe2x80x2) from a translation initiation codon. This region is a preferred target region. Similarly, the terms xe2x80x9cstop codon regionxe2x80x9d and xe2x80x9ctranslation termination codon regionxe2x80x9d refer to a portion of such an mRNA or gene that encompasses from about 25 to about 50 contiguous nucleotides in either direction (i.e., 5xe2x80x2 or 3xe2x80x2) from a translation termination codon. This region is a preferred target region. The open reading frame (ORF) or xe2x80x9ccoding region,xe2x80x9d which is known in the art to refer to the region between the translation initiation codon and the translation termination codon, is also a region which may be targeted effectively. Other preferred target regions include the 5xe2x80x2 untranslated region (5xe2x80x2UTR), known in the art to refer to the portion of an mRNA in the 5xe2x80x2 direction from the translation initiation codon, and thus including nucleotides between the 5xe2x80x2 cap site and the translation initiation codon of an mRNA or corresponding nucleotides on the gene) and the 3xe2x80x2 untranslated region (3xe2x80x2UTR), known in the art to refer to the portion of an mRNA in the 3xe2x80x2 direction from the translation termination codon, and thus including nucleotides between the translation termination codon and 3xe2x80x2 end of an mRNA or corresponding nucleotides on the gene). mRNA splice sites may also be preferred target regions, and are particularly useful in situations where aberrant splicing is implicated in disease, or where an overproduction of a particular mRNA splice product is implicated in disease. Aberrant fusion junctions due to rearrangements or deletions may also be preferred targets.
Once the target site or sites have been identified, oligonucleotides are chosen which are sufficiently complementary to the target, i.e., hybridize sufficiently well and with sufficient specificity, to give the desired modulation.
xe2x80x9cHybridizationxe2x80x9d, in the context of this invention, means hydrogen bonding, also known as Watson-Crick base pairing, between complementary bases, usually on opposite nucleic acid strands or two regions of a nucleic acid strand. Guanine and cytosine are examples of complementary bases which are known to form three hydrogen bonds between them. Adenine and thymine are examples of complementary bases which form two hydrogen bonds between them.
xe2x80x9cSpecifically hybridizablexe2x80x9d and xe2x80x9ccomplementaryxe2x80x9d are terms which are used to indicate a sufficient degree of complementarity such that stable and specific binding occurs between the DNA or RNA target and the oligonucleotide.
It is understood that an oligonucleotide need not be 100% complementary to its target nucleic acid sequence to be specifically hybridizable. An oligonucleotide is specifically hybridizable when binding of the oligonucleotide to the target interferes with the normal function of the target molecule to cause a loss of utility, and there is a sufficient degree of complementarity to avoid non-specific binding of the oligonucleotide to non-target sequences under conditions in which specific binding is desired, i.e., under physiological conditions in the case of in vivo assays or therapeutic treatment and, in the case of in vitro assays, under conditions in which the assays are conducted.
Hybridization of antisense oligonucleotides with mRNA interferes with one or more of the normal functions of mRNA. The functions of mRNA to be interfered with include all vital functions such as, for example, translocation of the RNA to the site of protein translation, translation of protein from the RNA, splicing of the RNA to yield one or more mRNA species, and catalytic activity which may be engaged in by the RNA.
The overall effect of interference with mRNA function is modulation of p38 MAPK expression. In the context of this invention xe2x80x9cmodulationxe2x80x9d means either inhibition or stimulation; i.e., either a decrease or increase in expression. This modulation can be measured in ways which are routine in the art, for example by Northern blot assay of mRNA expression as taught in the examples of the instant application or by Western blot or ELISA assay of protein expression, or by an immunoprecipitation assay of protein expression, as taught in the examples of the instant application. Effects on cell proliferation or tumor cell growth can also be measured, as taught in the examples of the instant application.
The oligonucleotides of this invention can be used in diagnostics, therapeutics, prophylaxis, and as research reagents and in kits. Since the oligonucleotides of this invention hybridize to nucleic acids encoding a p38 MAPK, sandwich, calorimetric and other assays can easily be constructed to exploit this fact. Furthermore, since the oligonucleotides of this invention hybridize specifically to nucleic acids encoding particular isoforms of p38 MAPK, such assays can be devised for screening of cells and tissues for particular p38 MAPK isoforms. Such assays can be utilized for diagnosis of diseases associated with various p38 MAPK isoforms. Provision of means for detecting hybridization of oligonucleotide with a p38 MAPK gene or mRNA can routinely be accomplished. Such provision may include enzyme conjugation, radiolabelling or any other suitable detection systems. Kits for detecting the presence or absence of p38 MAPK may also be prepared.
The present invention is also suitable for diagnosing abnormal inflammatory states in tissue or other samples from patients suspected of having an inflammatory disease such as rheumatoid arthritis. The ability of the oligonucleotides of the present invention to inhibit inflammation may be employed to diagnose such states. A number of assays may be formulated employing the present invention, which assays will commonly comprise contacting a tissue sample with an oligonucleotide of the invention under conditions selected to permit detection and, usually, quantitation of such inhibition. In the context of this invention, to xe2x80x9ccontactxe2x80x9d tissues or cells with an oligonucleotide or oligonucleotides means to add the oligonucleotide(s), usually in a liquid carrier, to a cell suspension or tissue sample, either in vitro or ex vivo, or to administer the oligonucleotide(s) to cells or tissues within an animal. Similarly, the present invention can be used to distinguish p38 MAPK-associated diseases, from diseases having other etiologies, in order that an efficacious treatment regime can be designed.
The oligonucleotides of this invention may also be used for research purposes. Thus, the specific hybridization exhibited by the oligonucleotides may be used for assays, purifications, cellular product preparations and in other methodologies which may be appreciated by persons of ordinary skill in the art.
In the context of this invention, the term xe2x80x9coligonucleotidexe2x80x9d refers to an oligomer or polymer of ribonucleic acid or deoxyribonucleic acid. This term includes oligonucleotides composed of naturally-occurring nucleobases, sugars and covalent intersugar (backbone) linkages as well as oligonucleotides having non-naturally-occurring portions which function similarly. Such modified or substituted oligonucleotides are often preferred over native forms because of desirable properties such as, for example, enhanced cellular uptake, enhanced binding to target and increased stability in the presence of nucleases.
The antisense compounds in accordance with this invention preferably comprise from about 5 to about 50 nucleobases. Particularly preferred are antisense oligonucleotides comprising from about 8 to about 30 nucleobases (i.e. from about 8 to about 30 linked nucleosides). Preferred embodiments comprise at least an 8-nucleobase portion of a sequence of an antisense compound which inhibits the expression of a p38 mitogen activated kinase. As is known in the art, a nucleoside is a base-sugar combination. The base portion of the nucleoside is normally a heterocyclic base. The two most common classes of such heterocyclic bases are the purines and the pyrimidines. Nucleotides are nucleosides that further include a phosphate group covalently linked to the sugar portion of the nucleoside. For those nucleosides that include a pentofuranosyl sugar, the phosphate group can be linked to either the 2=, 3= or 5=hydroxyl moiety of the sugar. In forming oligonucleotides, the phosphate groups covalently link adjacent nucleosides to one another to form a linear polymeric compound. In turn the respective ends of this linear polymeric structure can be further joined to form a circular structure, however, open linear structures are generally preferred. Within the oligonucleotide structure, the phosphate groups are commonly referred to as forming the internucleoside backbone of the oligonucleotide. The normal linkage or backbone of RNA and DNA is a 3= to 5=phosphodiester linkage.
Specific examples of some preferred modified oligonucleotides envisioned for this invention include those containing phosphorothioates, phosphotriesters, methyl phosphonates, short chain alkyl or cycloalkyl intersugar linkages or short chain heteroatomic or heterocyclic intersugar linkages. Most preferred are oligonucleotides with phosphorothioates (usually abbreviated in the art as Pxe2x95x90S) and those with CH2xe2x80x94NHxe2x80x94Oxe2x80x94CH2, CH2xe2x80x94N(CH3)xe2x80x94Oxe2x80x94CH2 [known as a methylene(methylimino) or MMI backbone], CH2xe2x80x94Oxe2x80x94N(CH3)xe2x80x94CH2, CH2xe2x80x94N(CH3)xe2x80x94N(CH3)xe2x80x94CH2 and Oxe2x80x94N(CH3)xe2x80x94CH2xe2x80x94CH2 backbones, wherein the native phosphodiester (usually abbreviated in the art as Pxe2x95x90O) backbone is represented as Oxe2x80x94Pxe2x80x94Oxe2x80x94CH2). Also preferred are oligonucleotides having morpholino backbone structures (Summerton and Weller, U.S. Pat. No. 5,034,506). Further preferred are oligonucleotides with NRxe2x80x94C(*)xe2x80x94CH2xe2x80x94CH2, CH2xe2x80x94NRxe2x80x94C(*)xe2x80x94CH2, CH2xe2x80x94CH2xe2x80x94NRxe2x80x94C(*), C(*)xe2x80x94NRxe2x80x94CH2xe2x80x94CH2 and CH2xe2x80x94C(*)xe2x80x94NRxe2x80x94CH2 backbones, wherein xe2x80x9c*xe2x80x9d represents O or S (known as amide backbones; DeMesmaeker et al., WO 92/20823, published Nov. 26, 1992). In other preferred embodiments, such as the peptide nucleic acid (PNA) backbone, the phosphodiester backbone of the oligonucleotide is replaced with a polyamide backbone, the nucleobases being bound directly or indirectly to the aza nitrogen atoms of the polyamide backbone (Nielsen et al., Science, 254, 1497 (1991); U.S. Pat. No. 5,539,082). Other preferred modified oligonucleotides may contain one or more substituted sugar moieties comprising one of the following at the 2xe2x80x2 position: OH, SH, SCH3, F, OCN, OCH3OCH3, OCH3O(CH2)nCH3, O(CH2)nNH2 or O(CH2)nCH3 where n is from 1 to about 10; C1 to C10 lower alkyl, alkoxyalkoxy, substituted lower alkyl, alkaryl or aralkyl; Cl; Br; CN; CF3; OCF3; Oxe2x80x94, Sxe2x80x94, or N-alkyl; Oxe2x80x94, Sxe2x80x94, or N-alkenyl; SOCH3; SO2CH3; ONO2; NO2; N3; NH2; heterocycloalkyl; heterocycloalkaryl; aminoalkylamino; polyalkylamino; substituted silyl; an RNA cleaving group; a reporter group; an intercalator; a group for improving the pharmacokinetic properties of an oligonucleotide; or a group for improving the pharmacodynamic properties of an oligonucleotide and other substituents having similar properties. A preferred modification includes 2xe2x80x2-O-methoxyethyl [which can be written as 2xe2x80x2-Oxe2x80x94CH2CH2OCH3, and is also known in the art as 2xe2x80x2-Oxe2x80x94(2-methoxyethyl) or 2xe2x80x2-methoxyethoxy] [Martin et al., Helv. Chim. Acta, 78, 486 (1995)]. Other preferred modifications include 2xe2x80x2-methoxy (2xe2x80x2-Oxe2x80x94CH3), 2xe2x80x2-propoxy (2xe2x80x2-OCH2CH2CH3), 2xe2x80x2-aminopropoxy (2xe2x80x2-OCH2CH2CH2NH2) and 2xe2x80x2-fluoro (2xe2x80x2-F). A further preferred modification includes 2xe2x80x2-dimethylaminooxyethoxy, i.e., a O(CH2)2ON(CH3)2 group, also known as 2xe2x80x2-DMAOE, as described in examples hereinbelow. Similar modifications may also be made at other positions on the oligonucleotide, particularly the 3xe2x80x2 position of the sugar on the 3xe2x80x2 terminal nucleotide and the 5xe2x80x2 position of the 5xe2x80x2 terminal nucleotide. Oligonucleotides may also have sugar mimetics such as cyclobutyls in place of the pentofuranosyl group.
The oligonucleotides of the invention may additionally or alternatively include nucleobase modifications or substitutions. As used herein, xe2x80x9cunmodifiedxe2x80x9d or xe2x80x9cnaturalxe2x80x9d nucleobases include adenine (A), guanine (G), thymine (T), cytosine (C) and uracil (U). Modified nucleobases include nucleobases found only infrequently or transiently in natural nucleic acids, e.g., hypoxanthine, 6-methyladenine and 5-methylcytosine, as well as synthetic nucleobases, e.g., 5-bromouracil, 5-hydroxymethyluracil, 8-azaguanine, 7-deazaguanine, N6(6-aminohexyl)adenine and 2,6-diaminopurine [Kornberg, A., DNA Replication, 1974, W. H. Freeman and Co., San Francisco, 1974, pp. 75-77; Gebeyehu, G., et al., Nucleic Acids Res., 15, 4513 (1987)]. 5-methylcytosine (5-me-C) is presently a preferred nucleobase, particularly in combination with 2xe2x80x2-O-methoxyethyl modifications.
Another preferred additional or alternative modification of the oligonucleotides of the invention involves chemically linking to the oligonucleotide one or more lipophilic moieties which enhance the cellular uptake of the oligonucleotide. Such lipophilic moieties may be linked to an oligonucleotide at several different positions on the oligonucleotide. Some preferred positions include the 3xe2x80x2 position of the sugar of the 3xe2x80x2 terminal nucleotide, the 5xe2x80x2 position of the sugar of the 5xe2x80x2 terminal nucleotide, and the 21 position of the sugar of any nucleotide. The N6 position of a purine nucleobase may also be utilized to link a lipophilic moiety to an oligonucleotide of the invention (Gebeyehu, G., et al., Nucleic Acids Res., 1987, 15, 4513). Such lipophilic moieties include but are not limited to a cholesteryl moiety [Letsinger et al., Proc. Natl. Acad. Sci. USA,, 86, 6553 (1989)], cholic acid [Manoharan et al., Bioorg. Med. Chem. Let., 4, 1053 (1994)], a thioether, e.g., hexyl-S-tritylthiol [Manoharan et al., Ann. N.Y. Acad. Sci., 660, 306 (1992); Manoharan et al., Bioorg. Med. Chem. Let., 3, 2765 (1993)], a thiocholesterol [Oberhauser et al., Nucl. Acids Res., 20, 533 (1992)], an aliphatic chain, e.g., dodecandiol or undecyl residues [Saison-Behmoaras et al., EMBO J., 10, 111 (1991); Kabanov et al., FEBS Lett., 259, 327 (1990); Svinarchuk et al., Biochimie., 75, 49(1993)], a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate [Manoharan et al., Tetrahedron Lett., 36, 3651 (1995); Shea et al., Nucl. Acids Res., 18, 3777 (1990)], a polyamine or a polyethylene glycol chain [Manoharan et al., Nucleosides andNucleotides, 14, 969 (1995)], or adamantane acetic acid [Manoharan et al., Tetrahedron Lett., 36, 3651 (1995)], a palmityl moiety [Mishra et al., Biochim. Biophys. Acta, 1264, 229 (1995)], or an octadecylamine or hexylamino-carbonyl-oxycholesterol moiety [Crooke et al., J. Pharmacol. Exp. Ther., 277, 923 (1996)]. Oligonucleotides comprising lipophilic moieties, and methods for preparing such oligonucleotides, as disclosed in U.S. Pat. Nos. 5,138,045, 5,218,105 and 5,459,255, the contents of which are hereby incorporated by reference.
The present invention also includes oligonucleotides which are chimeric oligonucleotides. xe2x80x9cChimericxe2x80x9d oligonucleotides or xe2x80x9cchimeras,xe2x80x9d in the context of this invention, are oligonucleotides which contain two or more chemically distinct regions, each made up of at least one nucleotide. These oligonucleotides typically contain at least one region wherein the oligonucleotide is modified so as to confer upon the oligonucleotide increased resistance to nuclease degradation, increased cellular uptake, and/or increased binding affinity for the target nucleic acid. An additional region of the oligonucleotide may serve as a substrate for enzymes capable of cleaving RNA:DNA or RNA:RNA hybrids. By way of example, RNase H is a cellular endonuclease which cleaves the RNA strand of an RNA:DNA duplex. Activation of RNase H, therefore, results in cleavage of the RNA target, thereby greatly enhancing the efficiency of antisense inhibition of gene expression. Cleavage of the RNA target can be routinely detected by gel electrophoresis and, if necessary, associated nucleic acid hybridization techniques known in the art. This RNAse H-mediated cleavage of the RNA target is distinct from the use of ribozymes to cleave nucleic acids. Ribozymes are not comprehended by the present invention.
Examples of chimeric oligonucleotides include but are not limited to xe2x80x9cgapmers,xe2x80x9d in which three distinct regions are present, normally with a central region flanked by two regions which are chemically equivalent to each other but distinct from the gap. A preferred example of a gapmer is an oligonucleotide in which a central portion (the xe2x80x9cgapxe2x80x9d) of the oligonucleotide serves as a substrate for RNase H and is preferably composed of 2xe2x80x2-deoxynucleotides, while the flanking portions (the 5xe2x80x2 and 3xe2x80x2 xe2x80x9cwingsxe2x80x9d) are modified to have greater affinity for the target RNA molecule but are unable to support nuclease activity (e.g., 2xe2x80x2-fluoro- or 2xe2x80x2-O-methoxyethyl-substituted). Other chimeras include xe2x80x9cwingmers,xe2x80x9d also known in the art as xe2x80x9chemimers,xe2x80x9d that is, oligonucleotides with two distinct regions. In a preferred example of a wingmer, the 5xe2x80x2 portion of the oligonucleotide serves as a substrate for RNase H and is preferably composed of 2xe2x80x2-deoxynucleotides, whereas the 3xe2x80x2 portion is modified in such a fashion so as to have greater affinity for the target RNA molecule but is unable to support nuclease activity (e.g., 2xe2x80x2-fluoro- or 2xe2x80x2-O-methoxyethyl- substituted), or vice-versa. In one embodiment, the oligonucleotides of the present invention contain a 2xe2x80x2-O-methoxyethyl (2xe2x80x2-Oxe2x80x94CH2CH2OCH3) modification on the sugar moiety of at least one nucleotide. This modification has been shown to increase both affinity of the oligonucleotide for its target and nuclease resistance of the oligonucleotide. According to the invention, one, a plurality, or all of the nucleotide subunits of the oligonucleotides of the invention may bear a 2xe2x80x2-O-methoxyethyl (xe2x80x94Oxe2x80x94CH2CH2OCH3) modification. Oligonucleotides comprising a plurality of nucleotide subunits having a 2xe2x80x2-O-methoxyethyl modification can have such a modification on any of the nucleotide subunits within the oligonucleotide, and may be chimeric oligonucleotides. Aside from or in addition to 2xe2x80x2-O-methoxyethyl modifications, oligonucleotides containing other modifications which enhance antisense efficacy, potency or target affinity are also preferred. Chimeric oligonucleotides comprising one or more such modifications are presently preferred. Through use of such modifications, active oligonucleotides have been identified which are shorter than conventional xe2x80x9cfirst generationxe2x80x9d oligonucleotides active against p38. Oligonucleotides in accordance with this invention are from 5 to 50 nucleotides in length. In the context of this invention it is understood that this encompasses non-naturally occurring oligomers as hereinbefore described, having from 5 to 50 monomers.
The oligonucleotides used in accordance with this invention may be conveniently and routinely made through the well-known technique of solid phase synthesis. Equipment for such synthesis is sold by several vendors including Applied Biosystems. Any other means for such synthesis may also be employed; the actual synthesis of the oligonucleotides is well within the talents of the routineer. It is well known to use similar techniques to prepare oligonucleotides such as the phosphorothioates and 2xe2x80x2-alkoxy or 2xe2x80x2-alkoxyalkoxy derivatives, including 2xe2x80x2-O-methoxyethyl oligonucleotides [Martin, P., Helv. Chim. Acta, 78, 486 (1995)]. It is also well known to use similar techniques and commercially available modified amidites and controlled-pore glass (CPG) products such as biotin, fluorescein, acridine or psoralen-modified amidites and/or CPG (available from Glen Research, Sterling Va.) to synthesize fluorescently labeled, biotinylated or other conjugated oligonucleotides.
The antisense compounds of the present invention include bioequivalent compounds, including pharmaceutically acceptable salts and prodrugs. This is intended to encompass any pharmaceutically acceptable salts, esters, or salts of such esters, or any other compound which, upon administration to an animal including a human, is capable of providing (directly or indirectly) the biologically active metabolite or residue thereof. Accordingly, for example, the disclosure is also drawn to pharmaceutically acceptable salts of the nucleic acids of the invention and prodrugs of such nucleic acids.
Pharmaceutically acceptable xe2x80x9csaltsxe2x80x9d are physiologically and pharmaceutically acceptable salts of the nucleic acids of the invention: i.e., salts that retain the desired biological activity of the parent compound and do not impart undesired toxicological effects thereto [see, for example, Berge et al., xe2x80x9cPharmaceutical Salts,xe2x80x9d J. of Pharma Sci., 66:1 (1977)].
For oligonucleotides, examples of pharmaceutically acceptable salts include but are not limited to (a) salts formed with cations such as sodium, potassium, ammonium, magnesium, calcium, polyamines such as spermine and spermidine, etc.; (b) acid addition salts formed with inorganic acids, for example hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid and the like; (c) salts formed with organic acids such as, for example, acetic acid, oxalic acid, tartaric acid, succinic acid, maleic acid, fumaric acid, gluconic acid, citric acid, malic acid, ascorbic acid, benzoic acid, tannic acid, palmitic acid, alginic acid, polyglutamic acid, naphthalenesulfonic acid, methanesulfonic acid, p-toluenesulfonic acid, naphthalenedisulfonic acid, polygalacturonic acid, and the like; and (d) salts formed from elemental anions such as chlorine, bromine, and iodine.
The oligonucleotides of the invention may additionally or alternatively be prepared to be delivered in a xe2x80x9cprodrugxe2x80x9d form. The term xe2x80x9cprodrugxe2x80x9d indicates a therapeutic agent that is prepared in an inactive form that is converted to an active form (i.e., drug) within the body or cells thereof by the action of endogenous enzymes or other chemicals and/or conditions. In particular, prodrug versions of the oligonucleotides of the invention are prepared as SATE [(S-acetyl-2-thioethyl) phosphate] derivatives according to the methods disclosed in WO 93/24510 to Gosselin et al., published Dec. 9, 1993.
For therapeutic or prophylactic treatment, oligonucleotides are administered in accordance with this invention. Oligonucleotide compounds of the invention may be formulated in a pharmaceutical composition, which may include pharmaceutically acceptable carriers, thickeners, diluents, buffers, preservatives, surface active agents, neutral or cationic lipids, lipid complexes, liposomes, penetration enhancers, carrier compounds and other pharmaceutically acceptable carriers or excipients and the like in addition to the oligonucleotide. Such compositions and formulations are comprehended by the present invention.
Pharmaceutical compositions comprising the oligonucleotides of the present invention may include penetration enhancers in order to enhance the alimentary delivery of the oligonucleotides. Penetration enhancers may be classified as belonging to one of five broad categories, i.e., fatty acids, bile salts, chelating agents, surfactants and non-surfactants (Lee et al., Critical Reviews in Therapeutic Drug Carrier Systems, 1991, 8:91-192; Muranishi, Critical Reviews in Therapeutic Drug Carrier Systems, 1990, 7:1). One or more penetration enhancers from one or more of these broad categories may be included.
The compositions of the present invention may additionally contain other adjunct components conventionally found in pharmaceutical compositions, at their art-established usage levels. Thus, for example, the compositions may contain additional compatible pharmaceutically-active materials such as, e.g., antipruritics, astringents, local anesthetics or anti-inflammatory agents, or may contain additional materials useful in physically formulating various dosage forms of the composition of present invention, such as dyes, flavoring agents, preservatives, antioxidants, opacifiers, thickening agents and stabilizers. However, such materials, when added, should not unduly interfere with the biological activities of the components of the compositions of the invention.
Regardless of the method by which the oligonucleotides of the invention are introduced into a patient, colloidal dispersion systems may be used as delivery vehicles to enhance the in vivo stability of the oligonucleotides and/or to target the oligonucleotides to a particular organ, tissue or cell type. Colloidal dispersion systems include, but are not limited to, macromolecule complexes, nanocapsules, microspheres, beads and lipid-based systems including oil-in-water emulsions, micelles, mixed micelles, liposomes and lipid:oligonucleotide complexes of uncharacterized structure. A preferred colloidal dispersion system is a plurality of liposomes. Liposomes are microscopic spheres having an aqueous core surrounded by one or more outer layers made up of lipids arranged in a bilayer configuration [see, generally, Chonn et al., Current Op. Biotech., 6, 698 (1995)].
The pharmaceutical compositions of the present invention may be administered in a number of ways depending upon whether local or systemic treatment is desired and upon the area to be treated. Administration may be topical (including ophthalmic, vaginal, rectal, intranasal, epidermal and transdermal), oral or parenteral. Parenteral administration includes intravenous drip, subcutaneous, intraperitoneal or intramuscular injection, pulmonary administration, e.g., by inhalation or insufflation, or intracranial, e.g., intrathecal or intraventricular, administration. oligonucleotides with at least one 2xe2x80x2-O-methoxyethyl modification are believed to be particularly useful for oral administration.
Formulations for topical administration may include transdermal patches, ointments, lotions, creams, gels, drops, suppositories, sprays, liquids and powders. Conventional pharmaceutical carriers, aqueous, powder or oily bases, thickeners and the like may be necessary or desirable. Coated condoms, gloves and the like may also be useful.
Compositions for oral administration include powders or granules, suspensions or solutions in water or non-aqueous media, capsules, sachets or tablets. Thickeners, flavoring agents, diluents, emulsifiers, dispersing aids or binders may be desirable.
Compositions for parenteral administration may include sterile aqueous solutions which may also contain buffers, diluents and other suitable additives. In some cases it may be more effective to treat a patient with an oligonucleotide of the invention in conjunction with other traditional therapeutic modalities in order to increase the efficacy of a treatment regimen. In the context of the invention, the term xe2x80x9ctreatment regimenxe2x80x9d is meant to encompass therapeutic, palliative and prophylactic modalities. For example, a patient may be treated with conventional chemotherapeutic agents, particularly those used for tumor and cancer treatment. Examples of such chemotherapeutic agents include but are not limited to daunorubicin, daunomycin, dactinomycin, doxorubicin, epirubicin, idarubicin, esorubicin, bleomycin, mafosfamide, ifosfamide, cytosine arabinoside, bis-chloroethylnitrosurea, busulfan, mitomycin C, actinomycin D, mithramycin, prednisone, hydroxyprogesterone, testosterone, tamoxifen, dacarbazine, procarbazine, hexamethylmelamine, pentamethylmelamine, mitoxantrone, amsacrine, chlorambucil, methylcyclohexylnitrosurea, nitrogen mustards, melphalan, cyclophosphamide, 6-mercaptopurine, 6-thioguanine, cytarabine (CA), 5-azacytidine, hydroxyurea, deoxycoformycin, 4-hydroxyperoxycyclophosphoramide, 5-fluorouracil (5-FU), 5-fluorodeoxyuridine (5-FUdR), methotrexate (MTX), colchicine, taxol, vincristine, vinblastine, etoposide, trimetrexate, teniposide, cisplatin and diethylstilbestrol (DES). See, generally, The Merck Manual of Diagnosis and Therapy, 15th Ed., pp. 1206-1228, Berkow et al., eds., Rahay, N.J., 1987). When used with the compounds of the invention, such chemotherapeutic agents may be used individually (e.g., 5-FU and oligonucleotide), sequentially (e.g., 5-FU and oligonucleotide for a period of time followed by MTX and oligonucleotide), or in combination with one or more other such chemotherapeutic agents (e.g., 5-FU, MTX and oligonucleotide, or 5-FU, radiotherapy and oligonucleotide).
The formulation of therapeutic compositions and their subsequent administration is believed to be within the skill of those in the art. Dosing is dependent on severity and responsiveness of the disease state to be treated, with the course of treatment lasting from several days to several months, or until a cure is effected or a diminution of the disease state is achieved. Optimal dosing schedules can be calculated from measurements of drug accumulation in the body of the patient. Persons of ordinary skill can easily determine optimum dosages, dosing methodologies and repetition rates. Optimum dosages may vary depending on the relative potency of individual oligonucleotides, and can generally be estimated based on EC50s found to be effective in in vitro and in vivo animal models. In general, dosage is from 0.01 xcexcg to 100 g per kg of body weight, and may be given once or more daily, weekly, monthly or yearly, or even once every 2 to 20 years. Persons of ordinary skill in the art can easily estimate repetition rates for dosing based on measured residence times and concentrations of the drug in bodily fluids or tissues. Following successful treatment, it may be desirable to have the patient undergo maintenance therapy to prevent the recurrence of the disease state, wherein the oligonucleotide is administered in maintenance doses, ranging from 0.01 xcexcg to 100 g per kg of body weight, once or more daily, to once every 20 years.
Thus, in the context of this invention, by xe2x80x9ctherapeutically effective amountxe2x80x9d is meant the amount of the compound which is required to have a therapeutic effect on the treated mammal. This amount, which will be apparent to the skilled artisan, will depend upon the type of mammal, the age and weight of the mammal, the type of disease to be treated, perhaps even the gender of the mammal, and other factors which are routinely taken into consideration when treating a mammal with a disease. A therapeutic effect is assessed in the mammal by measuring the effect of the compound on the disease state in the animal. For example, if the disease to be treated is cancer, therapeutic effects are assessed by measuring the rate of growth or the size of the tumor, or by measuring the production of compounds such as cytokines, production of which is an indication of the progress or regression of the tumor.
The following examples illustrate the present invention and are not intended to limit the same.